14.01.2026

Specific heat capacity: clever architectural use

Building design

Low-angle view of the Geisel Library at UCSD by Zongnan Bao - a symbol of innovative sustainable architecture with concrete.

Storing heat like a pro? The specific heat capacity sounds like a physics lesson, but it has long been the deciding factor for clever floor plans, sustainable materials and the future of construction. Anyone who only counts U-values has done the math without the physics – and is wasting architectural potential. It’s time to finally think big about the inconspicuous measure of heat quantity in everyday architecture.

What the specific heat capacity means in technical terms and why architects should be interested in it.
How targeted material selection influences the indoor climate of buildings – and saves costs.
Why Germany, Austria and Switzerland deal with thermal mass differently.
The most important innovations and digital tools relating to thermal simulations and AI.
Sustainability aspects: How thermal storage saves gray energy and reduces the CO₂ footprint.
What technical knowledge counts today in planning, execution and building operation.
Where myths, misunderstandings and debates lurk when dealing with specific heat capacity
How European and global trends are driving the topic forward – or slowing it down.

Specific heat capacity – physics for architects, not nerds

In theory, the specific heat capacity, often referred to as c, is the amount of heat energy that one kilogram of a substance requires to heat up by one degree Celsius. Sounds dry, but it’s a real game changer for architecture. While many planners focus on U-values, lambda and insulation thicknesses, the heat storage capacity of materials often remains under the radar. Yet it is one of the factors that determines whether a house becomes an oven in midsummer or not, whether the heating has to come on at night or whether the large south-facing window provides more than just a view.

In practice, this means that solid building materials such as concrete, brick or clay can absorb a lot of heat and release it slowly. Lightweight construction methods lose this ability almost completely. The result? The daily temperature curve in the room is smoothed out, heating and cooling loads are reduced and comfort is increased. This sounds like old wisdom, but in times of passive houses, plus energy and climate resilience, it is more relevant than ever. Because with the right material strategy, energy peaks can be reduced – without any high-tech.

Germany, Austria and Switzerland have surprisingly different approaches to thermal storage capacity. While solid brick construction and exposed concrete are still considered the measure of all things in the Alpine region, Germany is focusing on lightweight construction in many places – often due to cost pressure or obsession with standards. Switzerland, on the other hand, is testing hybrid approaches in which materials are specifically combined according to their thermal capacity. The consequence: anyone who ignores the specific heat capacity is planning without taking comfort and sustainability into account.

The fact that the topic is often neglected in the design phase is also due to the complexity of the interplay between mass, surface and use. A large storage tank is not automatically better – the decisive factor is the position of the mass in relation to the thermal envelope and the internal loads. This is where the wheat is separated from the chaff: if you only rely on insulation, you will have a problem in summer. If you store cleverly, you win twice over – in terms of energy consumption and user comfort.

Architects who internalize this principle can get the maximum out of a building with simple means. Specific heat capacity is not an end in itself, but a clever combination of physics and space. It is the invisible backbone of sustainable, comfortable construction – and it forces planners to think beyond standard solutions.

Technology, simulation and AI – how digitalization is rethinking thermal capacity

You can twist and turn it however you like: without digital tools, specific thermal capacity remains an elusive construct. Today, modern simulation software makes possible what was previously only possible through experience and gut feeling. Programs such as PHPP, EnergyPlus or TRNSYS calculate to the second how heat is distributed in different building components, how quickly rooms cool down or heat up, and how efficiency potential can be tapped.

However, the real game changer is not simulation alone, but the integration of AI-based algorithms. Artificial intelligence can optimize material combinations and room concepts in such a way that not only energy targets are achieved, but also comfort and costs remain in balance. In Germany, such tools have long been used in the planning of passive houses and complex office buildings, and interest is growing exponentially in Switzerland and Austria. The trend is moving away from rigid specifications towards flexible, data-driven design processes – in which the specific thermal capacity is no longer used as a disruptive factor, but as a design resource.

The highlight: digital twins can be used to run through thermal scenarios for entire neighborhoods. Which material strategy works in an old building, which in an urban timber module building? How does the indoor climate change when outside temperatures rise? The simulation does not replace gut feeling, but it finally makes the influence of thermal capacity visible and open to discussion. This not only provides planning security, but also the opportunity to test innovative construction methods – without real users becoming guinea pigs.

Another advantage of digitalization is that it brings transparency to the debate. Building owners, investors and users can compare how different material strategies affect energy costs and comfort. Suddenly, the physical characteristic value becomes a sales argument – and in times of ESG, taxonomy and CO₂ pricing, this is more than just a nice extra.

But as always, without a solid technical understanding, even the best tool is just a placebo. Anyone working with simulations must be familiar with the physical principles and know the limits of the models. Otherwise there is a risk that seemingly perfect solutions will fail miserably in reality. The specific heat capacity is not a value to tick off, but a tool for intelligent design – digital, but not arbitrary.

Sustainability reloaded – thermal capacity as a climate saver or energy ballast?

In the age of sustainability, specific heat capacity is more than just a technical detail. It determines how much gray energy a building stores, how often heating and cooling systems have to be activated – and how robust a building is against climate change and extreme weather. In Germany, the issue is primarily addressed via the EnEV, the Building Energy Act and various subsidy programs. However, real innovation is emerging beyond the paragraphs: those who use thermal mass in a targeted manner can cushion peak loads in the electricity grid, store photovoltaic power and make buildings fit for the summer – without any climate-damaging air conditioning systems.

Experience from Austria and Switzerland shows this: Massive buildings with a high thermal capacity can significantly reduce heating energy requirements – provided they are used correctly. But be careful: a high storage mass can also become a boomerang if it is placed incorrectly or cannot discharge at night. The classic example: poorly ventilated basements, over-insulated facades, lack of night-time cooling. This requires more than just thick walls – it requires an understanding of the entire life cycle of a building.

The debate about sustainable building materials is shifting the perspective even further. Wood, clay, recycled concrete, PCM (phase change materials) and innovative composite materials offer new opportunities to combine storage capacity with low emissions. Switzerland is already testing PCM elements that are installed in walls and ceilings and absorb or release heat depending on the temperature. Austria is experimenting with prefabricated clay modules and circular components. As is so often the case, Germany remains caught between innovation and standards bureaucracy, but is slowly discovering the potential of sustainable storage strategies.

From a global perspective, it is clear that specific heat capacity is becoming a competitive factor. Those who understand it can make buildings more resilient, more climate-friendly and more economical. Those who ignore it will pay the price – at the latest when temperatures rise and energy prices go through the roof. The question is no longer whether heat storage is relevant, but how it can become the basis of sustainable architecture.

This requires not only technical expertise, but also the courage to question traditional construction methods. The future belongs to hybrid concepts: lightweight constructions with targeted storage masses, smart controls, adaptive façades. Specific thermal capacity is the invisible lever that will take sustainable construction out of its niche – if it is finally used consistently.

Technology, debates and visions – why thermal capacity is reinventing planning

Specific heat capacity is not a buzzword, but has been part of building physics for decades. What is new is how it is being discussed and used today. There are clear camps among experts: some swear by massive storage masses, others see the future in lightweight construction – and point to fast construction times, flexibility and lower emissions. As is so often the case, the truth lies somewhere in between. The decisive factor is the intelligent combination: storage masses in the right places, targeted control through sensor technology, adaptive utilization concepts.

In Germany and Austria, heat capacity is still often seen as a “nice to have” – an add-on for particularly ambitious projects. In Switzerland, on the other hand, it is considered a natural part of planning, especially in the context of Minergie and passive house standards. Internationally, it is mainly Asian and Scandinavian countries that are experimenting with thermal storage strategies – and showing that comfort, efficiency and design need not be a contradiction in terms.

Digitalization and automation are expanding the possibilities: AI-based ventilation systems, smart shading and dynamic control of heat storage systems make it possible to use thermal mass in a more targeted way than ever before. This opens up new scope for architecture and technology – and at the same time calls for new skills. Today, planners who are familiar with thermal simulation, sensor technology and materials research have a clear advantage.

However, there is also debate and criticism: does a lot of storage mass make buildings too sluggish? Is the specific heat capacity overestimated because real user behavior and climate extremes are difficult to plan for? What happens if technical systems fail or are incorrectly adjusted? This shows that the best technology is only as good as its interaction with design, use and operation. Heat capacity is not a panacea – but it is a powerful tool if it is used in a targeted and intelligent way.

The vision? Buildings that store energy like a battery, regulate the indoor climate in a natural way and respond flexibly to user needs. Architecture that does not work against nature, but with it. And planners who are prepared to see physics as part of the creative process again – not as a tedious compulsory exercise on the drawing board.

Conclusion: Heat capacity – the underestimated joker in architecture

Specific heat capacity is far more than just a number on a data sheet. It is the physical backbone of intelligent, sustainable architecture. If you understand it, you can design buildings that work with the climate instead of against it. The innovations of recent years – from digital simulations and new materials to AI-supported control – make it easier than ever to use thermal mass in a targeted manner. Germany, Austria and Switzerland are on the right track, but the potential is far from exhausted. The future belongs to planners who bring physics, design and technology together – and finally take specific heat capacity out of its niche. Because one thing is certain: if you don’t store heat today, you’ll be heating and cooling twice tomorrow. And nobody can afford that anymore.

20.01.2025

Trade

What will the retail spaces of the future look like?

Building design

Management

Brick-and-mortar retailers are fighting back against competition from the Internet and developing new retail concepts.

Shopping centers and high streets will soon be superfluous because customers will order everything online anyway thanks to online retail. This was the theory of many market observers, but it is now clear that this is not the case. Brick-and-mortar retailers have long since taken measures to counter the competition from the Internet. They are developing new retail concepts and formats that have one thing in common: Stores as we used to know them are no longer really stores.

The trend towards new or modified location concepts prompted the research team at real estate company Catella to look into the question of whether increasing digital retail will make European retail spaces obsolete in the medium term. “The fact is that digitalization and demographic change will change demand patterns and lead to a reduction in retail space,” says Thomas Beyerle, Head of Research at the real estate company, summarizing the results.

The 28 EU member states currently have a total of around 590 million square meters of retail space, 510 to 550 million square meters of which will still be available in 2030 according to Catella’s forecast. So that doesn’t sound like a huge extinction of stores. Retailers are also finding new unique selling points in competition with e-commerce providers – for example, what Beyerle calls the “festivalization” of shopping: more and more providers, especially of high-quality products, are focusing on the experiential nature of shopping. Many retailers are therefore beginning to celebrate the shopping event and the brand in addition to the actual product.

A major project currently under construction in Switzerland, “The Circle at Zurich Airport”, is consistently geared towards such considerations: Riken Yamamoto has designed a building complex for the airport that is not only currently the largest building construction project in the country, but also aims to set new standards in terms of use. “The Circle” is no ordinary airport mall, but is intended to function like a city center, with narrow alleyways, small squares and a high quality of stay.

However, the area in which the retailers are to be located will differ significantly from a typical city center. Consequently, it is not called “Shopping Mall” at The Circle, but “Brands & Dialogue” – because this is not about shopping at all, but rather about trying out new formats for customer loyalty. For example, the luxury watch brand Omega will open a “Brand House” here. The focus is not on selling watches, only a very small store is planned. However, a large part of the 800 square meters will be occupied by a show workshop. Up to 40 employees will introduce visitors to the art of Swiss watchmaking and show how a ceramic movement works or how dials are made.

Another trend topic and unique selling point of the stationary retail trade that real estate professionals are currently talking about is the combination of retail and gastronomy. Many industry observers consider the Italian concept Eataly, which opened its first European location outside Italy last November in the converted Schrannenhalle in Munich, to be a prime example of this. The 4,600 square meter space houses 16 restaurants and food stalls, a shopping area with 10,000 delicatessen products and a cooking school – and even a small store for the traditional bicycle brand Bianchi. Eataly was founded in 2007 and is considered one of the fastest growing and most successful food service and retail companies with a recent turnover of around 400 million euros. The concept combines markets, restaurants, teaching facilities and show productions of Italian food under one roof – and prefers to rent space in prominent locations. The world’s largest branch, Eataly Alti Cibi, is located on Fifth Avenue in New York, directly opposite the Flatiron Building.

Whether watch workshop, restaurant or cooking school – the common goal of these retail concepts is to create a sensual counterpoint to sober online shopping. And the formats are quite space-intensive, usually covering around a thousand square meters or, as in the case of Eataly in Munich, many times that amount. However, the future of retail can also be seen in small spaces, where the connection between offline and online retail is being tested. The sporting goods retailer Decathlon, for example, known for its huge stores near the highway, launched its new concept called “Decathlon Connect” in February 2016 with its first city store on Munich’s Stachus.

In the stores of this format, the focus is on networking with the online store and other digital services: customers can have the sporting goods purchased via the online store delivered to the Connect store. There, the goods can be tested, tried on and exchanged if they are not to their liking when they pick them up. On-site tablets can be used to search for other collections, colors or models, which can also be ordered directly in the store.
Decathlon only needs a comparatively small space for this: The store on Stachus is 220 square meters in size; another Decathlon Connect has since opened on Königstraße in Stuttgart with just 50 square meters of space. Electronics retailer Saturn and toy chain Toys’R’Us, among others, have also introduced similar formats. In view of these new retail concepts, it is reasonable to assume that malls, shopping centers and inner-city shopping streets will change their face in the coming years; Catella researchers also assume this. However, Beyerle is convinced that bricks-and-mortar retail centers will retain one of their most important functions: “Increasing digitalization and constant networking will not replace the need for physical, social contact, but will complement it and demand it more than ever.” In the retail spaces of the future, the aspect of shopping will therefore only represent a partial element. At best, they will be places where urban life pulsates.

19.12.2024

Save the tombs!

Building design

Crypt archaeology? Another archaeology within an increasingly differentiated and specialized discipline? Crypt archaeology is still difficult to google, and there is no Wikipedia article either. The term probably first appeared in 2011 at the conference called “Transmortale”, which was jointly organized by the University of Hamburg and the Museum for Sepulchral Culture in Kassel. The […]

Crypt archaeology? Another archaeology within an increasingly differentiated and specialized discipline?

Crypt archaeology is still difficult to google, and there is no Wikipedia article either. The term probably first appeared in 2011 at the conference called “Transmortale”, which was jointly organized by the University of Hamburg and the Museum for Sepulchral Culture in Kassel. The protagonists who presented the topic are the same people who are now responsible for the book to be published. Some of them have been working underground for much longer, documenting crypts, struggling with fungal and mold infestation and often enough not only with the natural phenomena of transience, but also with the consequences of incorrect measures taken in the past or even with pure vandalism. And what can you do when twisted coffins are piled on top of each other in the crypt? What to do with the often mummified mortal remains, their clothing and grave goods? What can be saved, restored and perhaps made accessible to the public, how, with what effort and with what result? The collective of authors is also confronted with ethical questions. What should we do with these bodies that were laid to rest here for eternity some time ago? And they by no means leave it at reverence, but also shed light on the legal background when it comes to the ownership of the bodies or burial objects.

The topic certainly has a future, as burial vaults are increasingly being (re)discovered due to the growing awareness of priests, cemetery administrators, castle and mausoleum owners. Especially since the Reformation, the need for such exclusive burial sites has increased among the upper classes. Crypts can be found under almost every church that once had a noble patron who established his family burial place there. And as late as the 18th and 19th centuries, parishes were still building basements under their churches to create space for grand burial crypts. And what becomes of them once they have been restored – if the money was available? The interdisciplinary group of authors, ranging from archaeologists, historians and lawyers to textile restorers, addresses all these questions and proposes solutions that draw on a wealth of experience.

Although the “Cemetery Culture Today” series published by the Frankfurt University of Applied Sciences is primarily aimed at specialists in the cemetery sector, monument conservators, art historians and restorers will also find this book useful if they ever have to deal with the sepulchral underworld. And that will be the case more and more often. Above all, the case studies described provide suggestions as to how different the approach and results can be. It is not a guideline that should be followed when working on crypts in general, but rather documents that every crypt is different. You will not be overwhelmed by the size of the book, but it remains pleasingly compact and moderately priced. If you want to find out more about crypt archaeology, this is the book for you – but it is the only one currently available.

Preuß, Dirk et alii (ed.): Saving tombs! Ein Leitfaden zum pietätvollen Umgang mit historischen Grüften (Schriftenreihe Friedhofskultur heute, Vol. 5), Frankfurt/M 2014. ISBN 978-3-943787-29-0, 156 pages, 16 pages of color photos, € 18.